CN101032111B - A method, system and device for transmitting data in a MIMO telecommunication system - Google Patents

Abstract

The invention relates to a method for transmitting data between a transmitter equipped with at least two transmitting antennas (ta1, ta2.. taNt) and a receiver. The method according to the invention also comprises a symbol spreading step in which the components Zij (where i 1 to S and j 1 to Nt) of a predetermined number of consecutive symbols ZI... ZS will be spread over time before being transmitted via said transmitting antennas (ta1, ta2.. taNt). The data transmitted at any given instant will therefore not represent a single symbol Zi (where i ═ 1 to S), as is the case in known MIMO systems, but will represent a mixture between Nt components of S consecutive symbols, which introduces data diversity with respect to time, as perceived at the receiver end.

Description

A method, system and device for transmitting data in a MIMO telecommunication system

technical field

The invention relates to a method for transmitting data in a telecommunication system comprising at least one transmitter equipped with at least two transmitting antennas and at least one receiver equipped with at least one receiving antenna, the method comprising a symbol encoding step, Used to generate symbols to be sent over the communication channel established between the transmit and receive antennas. the

Background technique

A telecommunication system in which multiple antennas are used at the receiver end and/or at the transmitter end of a wireless link is called a multiple-input multiple-output system (also called a MIMO system). MIMO systems have been shown to provide a large transmission capacity compared to that provided by a single antenna system. Specifically, for a given signal-to-noise ratio and under well uncorrelated channel conditions, MIMO capacity increases linearly with the smallest number of transmit or receive antennas. MIMO techniques may thus be used in future wireless systems aimed at providing large spectral efficiencies, or reducing the transmit power required to obtain spectral efficiencies comparable to those obtained in current telecommunication systems. Such MIMO techniques will likely be combined with multicarrier modulation techniques like OFDM (standing for Orthogonal Frequency Division Multiplexing) and MC-CDMA (standing for Multicarrier Code Division Multiple Access) techniques, which are also considered for future wireless systems. the

A particular type of MIMO system utilizes a bit-interleaved coded modulation technique, also known as BICM, according to which the transmitter includes a channel coder for applying a code to the uncoded data bits, for example by means of a convolutional code or a turbo code, And is used to provide the binary stream to the interleaver. This interleaver will then deliver permuted bits that will be divided into word sequences that will be converted into a sequence of coded symbols, each coded symbol having multiple components, with components of the same symbol during the same time slice with individual The transmit antenna transmits. the

The transmitted symbols will be decoded at the receiver, usually performed in BICM-type MIMO systems using an iterative space-time decoder that produces estimates of the coded bits that make up the transmitted symbols. This decoding is facilitated by the spatial diversity resulting from the use of multiple transmit and receive antennas, since this diversity provides a greater amount of information than that provided by a single signal sent over a single communication channel. the

The inventors have noticed that increasing the diversity of the input data perceived by a front-end detector included in a spatio-temporal decoder allows the decoder to converge more quickly to a reliable estimate of the coded bits from which the data was produced. This can be seen as better decoding performance by providing the decoder with data of higher quality, ie richer content. the

The spatial diversity obtained by utilizing multiple communication channels perceived by the receiving antennas, while yielding the above advantages, is limited by the number of receiving antennas, which in turn limits the performance of the space-time decoder. the

Contents of the invention

The present invention solves the above-mentioned problems by providing a method for transmitting data in a MIMO system, which method involves a coding scheme allowing to provide high data diversity with respect to space and time, as at the receiver end of such telecommunication systems Perceived by at least one receive antenna. the

An aspect of the present invention provides a method for transmitting data in a telecommunication system, the telecommunication system comprising: at least one transmitter configured with at least two transmit antennas; and at least one receiver configured with at least one receive antenna . The method comprises: a symbol encoding step for generating symbols to be transmitted on a communication channel established between a transmitting antenna and a receiving antenna; a symbol expanding step by concatenating components of each consecutive symbol in a predetermined number of consecutive symbols multiplying the formed vector by a predetermined spreading matrix and generating a linear combination of said components; and a step of transmitting said linear combination over said transmit antenna over a number of time slices equal to a predetermined number of consecutive symbols. Wherein said predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmitting antennas and forming corresponding vectors all having the same norm. the

In fact, according to the invention, the method according to the opening paragraph is characterized in that it also comprises a symbol spreading step, in which the components of a predetermined number of consecutive symbols are to be spread over time before being transmitted via said communication channel. the

The present invention is able to combine the spatial diversity obtained by utilizing multiple communication channels established between the transmitting and receiving antennas, wherein the diversity of data with respect to time is perceived by the receiving antennas. the

According to a possible embodiment of the invention, the step of sign extension is performed by computing a number of linear combinations of the components of the vector representing said consecutive symbols, said linear combination. the

Data sent over multiple communication channels at any given instant will therefore not represent a single symbol, as is the case in MIMO systems known as described above, but will represent a mixture between components of successive symbols, which Diversity with respect to time is thus introduced. the

According to a particular embodiment of the invention, the step of sign extension is performed by, on the one hand, multiplying, on the one hand, a vector formed by the concatenation of the components of each of said consecutive symbols, by a predetermined spreading matrix on the other hand. the

Certain embodiments of the present invention are very easy to implement and thus enable increased diversity at a relatively low cost in terms of computational resources and processing power required at the transmitting end, which is an important issue in the field of mobile communications where the transmitter can be controlled by Mobile terminals such as mobile phones constitute which must be as small as possible and powered by batteries with limited energy storage. the

The properties of the predetermined spreading matrix may be selected based on a priori knowledge or based on assumptions about the communication channel to be established between the transmit and receive antennas. the

According to a first variant of the particular embodiment described above, the spreading matrix is constructed in such a way that each row of it is formed by successive blocks, each of which has a size corresponding to the number of transmitting antennas, forming any of the individual vectors All blocks of a given row all have the same norm. the

The spreading matrix according to this first variant achieves a substantially uniform distribution over time of the energy carried by the symbols sent over the ergodic communication channel, and guarantees optimal availability for changes in communication conditions from one time slice to another. Detective. This in turn allows to provide a high diversity of data with respect to time and space, as perceived by the receive antenna at the receiver end of such an ergodic communication channel. the

According to a second variant of the particular embodiment described above, the spreading matrix is constructed in such a way that each row of it is formed by successive blocks, each of which has a size corresponding to the number of transmitting antennas, forming any of the individual vectors All blocks of a given row all have the same norm and are mutually orthogonal. the

Due to the orthogonality between the blocks, the spreading matrix according to this second variant is able to add ergodicity to a substantially constant channel during the time interval required to transmit a linear combination of all components of a predetermined number of consecutive symbols, and There is also provided a substantially uniform distribution over this time interval of the energy carried by the symbols transmitted over said communication channel, which ensures optimum detectability of changes in communication conditions from one time slot to another. This in turn allows providing a high diversity of data with respect to time and space, as perceived by the receive antenna at the receiver end of such a substantially constant communication channel. the

According to a third variant of the particular embodiment described above, the extended matrix is constructed in such a way that each row of it consists of parts constituting the respective vectors all having the same norm, each part comprising successive blocks, each successive block The size of corresponds to the number of transmit antennas, and all blocks making up any given part of each vector all have the same norm and are mutually orthogonal. the

The spreading matrix according to this third variant is particularly suitable for so-called block fading communication channels, which are expected to have C consecutive sets of communication conditions over the entire transmission duration of components of a predetermined number S of consecutive symbols, said Each set of communication conditions for a block fading channel is thus substantially constant during the S/C time slice. the

Orthogonality between all blocks of the same segment can add ergodicity to a block-fading channel during each invariant period defined by these S/C time slices, equality of the norms of said blocks in turn provides The energy carried by the symbols transmitted over the block fading channel during the invariant periods is substantially evenly distributed over the invariant periods. the

Since the communication conditions in such a block fading channel change from one invariant period to another, the block fading channel can be considered as a scale ergodicity in the invariant period, so that the norm of the segment of each row expansion matrix The additional equality is sufficient to guarantee a substantially uniform distribution of the energy carried by symbols transmitted over a block-fading channel over all consecutive invariant periods. the

This in turn allows providing a high diversity of data with respect to time and space, as perceived by the receive antenna at the receiver end of such a block fading communication channel. the

According to a preferred embodiment of the first, second or third variant described above, the extension matrix will additionally have the properties of a rotation matrix, ie such an extension matrix will be composed of rows that are orthogonal to each other and have the same norm. the

Using rotation matrices to compute multiple linear combinations of the components of successive symbols at the transmitter allows optimizing the iterations used to process the symbols at the receiver by enhancing the performance of the first iterative process performed by the decoder Global performance of spatio-temporal decoders. the

Another aspect of the invention provides a telecommunication system comprising at least one transmitter configured with at least two transmit antennas and at least one receiver configured with at least one receive antenna. The transmitter comprises: symbol encoding means for generating symbols to be transmitted on a communication channel established between the transmitting antenna and the receiving antenna; multiplying the formed vector by a predetermined spreading matrix and generating a linear combination of said components; and transmitting means for transmitting said linear combination over said transmit antenna over a number of time slices equal to a predetermined number of consecutive symbols. Wherein, the predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmit antennas and forming corresponding vectors all having the same norm. the

According to a possible embodiment of this hardware-related aspect, the sign extension means are adapted to calculate a plurality of linear combinations of the components of the vector representing said consecutive symbols, which will be transmitted by means of the transmit antenna on a number of time slices equal to a predetermined number of consecutive symbols the above linear combination. the

According to a particular embodiment of the above-mentioned hardware-related aspect, the sign extension means is adapted to multiply, on the one hand, a vector formed by the concatenation of components of each of said consecutive symbols by a predetermined spreading matrix on the other hand. the

Another aspect of the present invention provides a communication device configured with at least two transmitting antennas and comprising: a symbol encoding unit for generating symbols to be transmitted on a communication channel established between the transmitting antenna and the receiving antenna; a symbol spreading unit , performed by multiplying a vector formed by concatenating the components of each consecutive symbol in a predetermined number of consecutive symbols by a predetermined spreading matrix, and producing a linear combination of said components; The linear combination is transmitted over a predetermined number of time slices of consecutive symbols. Wherein, the predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmit antennas and forming corresponding vectors all having the same norm. the

Description of drawings

The features of the present invention described above, as well as other features, will become more apparent after reading the following description with reference to the accompanying drawings, in which:

Figure 1 is a block diagram showing a very simplified MIMO telecommunication system;

Figure 2 is a block diagram showing a space-time encoder included in a transmitter according to the present invention, the transmitter being included in a MIMO telecommunication system;

Figure 3 is a diagram showing how the expansion step can be performed in such a spatio-temporal encoder according to the present invention;

Figure 4 is a diagram showing a channel matrix associated with an ergodic communication channel;

Figure 5 is a diagram showing a spreading matrix suitable for such an ergodic channel;

Figure 6 is a diagram showing a channel matrix associated with a block fading communication channel;

Figure 7 is a diagram showing a spreading matrix suitable for such a block fading communication channel; and

Figures 8 and 9 are diagrams showing techniques of how spreading matrices suitable for block fading communication channels can be constructed. the

Detailed ways

Fig. 1 shows schematically a telecommunication system comprising at least one transmitter TR and one receiver REC for transmitting the data through Nt transmitting antennas (ta1, ta2 ... taNt) and Nr receiving antennas and (ra1, taNt) respectively. A plurality of communication channels CHNL established between ra2...raNr) exchange signals. the

The transmitter TR shown in the example described here comprises a channel encoder CHENC for applying an encoding to the unencoded data bits Uncb, for example by convolutional codes or turbo codes, and providing a binary stream Tb to be transmitted. The transmitter TR comprises an interleaver INTL for generating permuted bits Pb, this interleaving is useful for post-processing on the receiver side as it will allow to obtain relevant data. Then, the rearranged bits Pb are divided into a sequence of Nt words of at least one bit each, and said sequence of words is then mapped, i.e. converted into a sequence of coded symbols Zi by the mapping and modulation module MAPMD, whereby each symbol Zi has Nt component. The consecutive symbols Zi are then supplied to a symbol encoding unit which is essentially constituted by a space-time encoder SPTENC which performs the processing of said symbols Zi before their transmission. the

In the known prior art, Nt components of each symbol Zi are transmitted by each transmit antenna taj (where j=1 to Nt) during the same time slice. the

The receiver REC shown in the example described here comprises a space-time decoder SPTDEC for generating decoded data bits Decb which should finally correspond to the original uncoded data bits Uncb. This space-time decoder SPTDEC comprises a space-time detector DET for processing the data carried by the signals received by the receiving antennas (ra1, ra2...raNr) and for generating A likelihood value Rib which will be deinterleaved by a deinterleaver DINTL which will output a soft likelihood value Rb related to the estimated value of the bits comprised in the binary stream Tb. A bit decoder included in the receiver REC, also called a channel decoder CHDEC, is used to generate decoded data bits Decb from said likelihood value Rb. the

According to the recurrent structure commonly used in this technique, the spatio-temporal detector DET will make use of the prior information Pra through the interleaver INTR generated during the above decoding step and issued by the channel decoder CHDEC in the form of extrinsic information Exd , the interleaver coincides with the interleaver included in the transmitter TR. the

The inventors have noticed that increasing the diversity of the data perceived by the space-time detector DET allows the decoder to converge more quickly to a reliable estimate of the coded bits from which the data was produced. Thus, the inventors have achieved an increase by Diversity of the data received by the receiving antennas (ra1, ra2...raNr), wherein the diversity of the data with respect to time, as perceived by the receiving antennas at the receiver end of said channel. the

Figure 2 shows schematically how such diversity can be obtained with the present invention. In fact, in the example described here, the space-time encoder SPTENC comprises a serial-to-parallel converter S/P for sequentially receiving the components of successive symbols Z1...ZS and delivering Nt components Zi1...ZiNt (where i= 1 to S) to the buffer BUF which delivers the S·Nt concatenated components of a single set of all consecutive symbols Z1...ZS to the sign extension means SPMD. This set of Ns=S·Nt components, after concatenation, constitutes a symbol vector Z representing said consecutive symbols Z1 . . . ZS. The sign extension part SPMD is in turn used to calculate the Ns linear combinations of the components Zij (where i=1 to S and j=1 to Nt) of the symbol vector Z, which are obtained by the Nt transmit antennas (ta1, ta2.. .taNt) are ordered by the sorting means SQM into S consecutive sets of Nt components before being transmitted on a number of time slices equal to a predetermined number S of consecutive symbols Z1...ZS whose components are included in said linear combination . the

Data transmitted at any given instant via multiple communication channels established between said transmit antennas (ta1, ta2...taNt) and said receive antennas will therefore not represent a single symbol Zi (where i=1 to S) , as is the case in known MIMO systems, will instead represent a mixture between Nt components of S consecutive symbols, so it introduces data diversity with respect to time, as perceived at the receiver end. Whereas in known MIMO systems of the type shown in the above figures the maximum diversity obtained is equal to the number Nr of receive antennas, whereby the maximum diversity achievable by the present invention will thus be equal to S·Nr. the

Figure 3 depicts how Ns linear combinations of components Zij (where i = 1 to S and j = 1 to Nt) of the sign vector Z represented here in the transposed form ^ZT can be computed by the above-described expansion means. According to a preferred embodiment of the present invention, the vector Z formed by the concatenation of all Nt components Zi1...ZiNt (where i=1 to S) of each of said consecutive symbols Zi is multiplied by a predetermined spreading matrix SM, in this instance , the predetermined spreading matrix SM has a size of Ns×Ns, capable of producing Ns individual linear combinations of all components Zij (where i=1 to S and j=1 to Nt) of the sign vector Z, which linear combinations are in S consecutive It is sent via Nt transmit antennas during the time slice.

Components Zij (where i = 1 to S and j = 1 to Nt) of the sign vector Z may consist of complex signs. In this case, the spreading matrix SM may be Ns×Ns in size and composed of complex components. An alternative approach may involve processing the real and imaginary parts of the complex components Zij separately by means of a spreading matrix SM of size (2·Ns)×(2·Ns) and comprising only real components. Thus, half of the 2 Ns real linear combinations produced by such a real spreading matrix SM will correspond to the real parts of the complex symbols to be transmitted on the Nt transmit antennas, while the 2 Ns produced by the real spreading matrix SM The other half of the real linear combination will correspond to the imaginary part of the complex symbols to be sent on the Nt transmit antennas. the

The properties of the predetermined spreading matrix SM can be chosen based on a priori knowledge or based on assumptions about the communication channel to be established between the transmit and receive antennas. the

Figure 4 represents the channel matrix H, describing the case where the communication channel is assumed to be ergodic, i.e. the communication conditions within the channel are expected to change at each of S time slices during which symbols will be transmitted S consecutive sets of Nt linear combinations of components Zij of vector Z (where i=1 to S and j=1 to Nt). It is modeled by S different diagonal blocks H1...Hs, each of size Nt×Nr. the

The inventors have found that high diversity will be obtained if the amount of data carried by such an ergodic communication channel is substantially uniform over time. This makes it possible to prevent the situation in which a high amount of data is present at the output of the communication channel at a given instant after which almost no data will appear at the output, which means time-dependent The information of will be easily detectable at said given instant, and will be hardly detectable thereafter. The substantially uniform distribution over time of the energy carried by the symbols sent over the ergodic communication channel guarantees optimal detectability of changes in communication conditions from one time slice to another, and thus enables the provision of High data diversity, as perceived by the receive antenna at the receiver end of such a communication channel. the

Fig. 5 depicts a spreading matrix SM according to a first variant of the preferred embodiment of the invention described above, according to which said spreading matrix SM has a structure particularly suitable for ergodic communication channels. In this example, the spreading matrix SM is constructed in such a way that its individual rows RWk (where k=1 to Ns) are formed from S consecutive blocks Chkl...Chks, the size of each block corresponds to the number Nt of transmitting antennas , all blocks forming any given row of the respective vectors all have the same norm, whereby the above-mentioned uniform distribution of the energy carried by the symbols sent over the ergodic communication channel can be obtained. the

In almost the opposite case to the ergodic case described above, a communication channel may be substantially constant, that is, the communication conditions within the channel are expected to remain the same for all S time slices, during which , S consecutive sets of Nt linear combinations of the components Zij of the symbol vector Z (where i = 1 to S and j = 1 to Nt) will be transmitted. the

In this case there will be no diversity with respect to time caused by the communication channel, which can be replaced by S identical diagonal blocks within the channel matrix H for the S different blocks H1... Hs to model. the

The inventors have found that by constructing the spreading matrix in such a way that each row of it is formed by successive blocks, each of which has a size corresponding to the number of transmitting antennas, all blocks of any given row of the respective vectors are formed All have the same norm and are mutually orthogonal so that a high time-dependent diversity can be obtained as perceived by the receive antenna at the receiver end of such a substantially constant channel. The extended matrix of this second variant according to the above-described preferred embodiment of the invention can thus be represented as the matrix SM given in Fig. 5, with the added condition that the blocks Chkl...Chks of any given row RWk are positive to each other pay. This orthogonality enables the simulation of the effect an ergodic communication channel would have on the set of transmitted linear combinations of components of consecutive symbols, and can thus be viewed as the time required to transmit all linear combinations of components of a predetermined number of consecutive symbols During the interval, a simulated transformation of a substantially constant channel to an ergodic channel is performed. As mentioned above, the fact that all blocks Chkl...Chks of any given row RWk all have the same norm enables to obtain a uniform distribution over time of the energy carried by the symbols transmitted over the artificially transformed communication channel. the

According to this second variant of the invention, a possible way of constructing such an extended matrix consists in choosing, for each given row of the extended matrix, a given square rotation matrix of size Nt×Nt, where Nt is greater than or equal to S, and S rows of this rotation matrix are selected to construct S consecutive blocks of said given row of the expansion matrix. the

Figure 6 represents a channel matrix H describing the case where the communication channel is considered to be a so-called block-fading channel, which is expected to have C consecutive sets of communication conditions over S time slices, during which the symbol vector Z will be transmitted S continuous sets of Nt linear combinations of the components Zij (where i=1 to S and j=1 to Nt), however, each set of communication conditions of the block fading channel substantially constitutes an invariant periodic S /C is constant during consecutive time slices. the

In this case, the channel matrix H includes C different diagonal blocks, and each diagonal block is composed of S/C identical diagonal sub-blocks respectively H1...Hc, each sub-block has its own Has a size of Nt×Nr. the

According to a third variant of the above-described preferred embodiment of the present invention, the spreading matrix SM is constructed in such a way that its individual rows RWk (wherein k=1 to Ns) are composed of C segments Sgkn (wherein n=1 to C), each segment Sgkn comprising successive blocks Chkn, l...Chkn, s/c, the size of each block corresponding to the number of transmit antennas, all blocks Chkn constituting any given segment of each vector, l...Chkn, s/c all have the same norm and are orthogonal to each other. the

Orthogonality between all blocks Chkn,l...Chkn,s/c of the same segment Sgkn enables adding ergodicity to block-fading channels during each invariant period defined by the corresponding S/C time slice, The equalization of the norms of the blocks Chkn,1...Chkn,s/c in turn provides that the energy carried by the symbols transmitted over the block fading channel during the invariant periods is substantially Uniform distribution of sex. Since the communication conditions in a block fading channel vary from one invariant period to another, the channel can be considered as scale ergodic in invariant period such that the rows RWk of the spreading matrix SM (where k=1 The additional equality of the norms of C segments Sgkn (where n = 1 to C) to Ns) is sufficient to guarantee a substantially uniform energy distribution over the S time slices during which symbols will be transmitted S consecutive sets of Nt linear combinations of components Zij of vector Z (where i=1 to S and j=1 to Nt). the

This in turn allows providing a high diversity of data with respect to time and space, as perceived by the receive antenna at the receiver end of such a block fading communication channel. the

Figures 8 and 9 illustrate how the spreading matrix SM according to this third variant of the above-described preferred embodiment of the invention can be constructed. the

In the first stage given in Fig. 8, by selecting a square secant rotation matrix CM of size Nt×Nt, where Nt is greater than or equal to S/C, and selecting the S/C rows of the matrix CM to form S/C consecutive diagonal blocks of Nt are used to form the diagonals of each sub-matrix S(W), thereby constructing C sub-matrices S(W), all such diagonal blocks thus have the same norm and are orthogonal to each other. the

Each component CM _m,1 of the cutting circle matrix CM can be expressed as:

${\mathrm{<span\; class="notranslate">\; CM</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; j\&pi;</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&Phi;</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; Nt</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; l</span>}}{\mathrm{<span\; class="notranslate">\; Nt</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

where Φ represents the Euler function. the

In the second stage given in Fig. 9, the matrix formed by the diagonal array of such submatrices S(w) (where w = 1 to C) of size Ns x Ns is multiplied by the matrix of size Ns x Ns its The components are given by another secant rotation matrix B, resulting in the expansion matrix SM. the

${\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; j\&pi;</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&Phi;</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; NS</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span>$

The extended matrix constructed as above will also have the property of a rotation matrix, i.e. such an extended matrix will be composed of rows that are orthogonal to each other and have the same norm, which can be expressed as SM × SM ^H = I, where I is the rank Ns × Ns identity matrix and SM ^H is the transformed conjugate value of matrix SM.

Using rotation matrices to calculate multiple linear combinations of the components of consecutive symbols at the transmitter can optimize the performance for processing the symbols at the receiver by enhancing the performance of the first iterative process performed by the decoder. Global performance of iterative spatiotemporal decoders. the

It should be understood that where the component Zij (where i=1 to S and j=1 to Nt) of the sign vector Z corresponding to it consists of complex symbols and the size of the spreading matrix SM is (2·Ns)×(2·Ns) and In an alternative embodiment comprising only the case of real components, the aforementioned blocks would each have a size corresponding to twice the number Nt of transmit antennas. the

Claims (12)

1. A method for transmitting data in a telecommunication system comprising: at least one transmitter configured with at least two transmit antennas; and at least one receiver configured with at least one receive antenna, the method include: a symbol encoding step for generating symbols to be transmitted on the communication channel established between the transmitting antenna and the receiving antenna; a sign extending step performed by multiplying a vector formed by concatenating components of each of a predetermined number of consecutive symbols by a predetermined spreading matrix and producing a linear combination of said components; and a transmitting step for transmitting said linear combination via said transmitting antenna over a number of time slices equal to a predetermined number of consecutive symbols, Wherein, the predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmit antennas and forming corresponding vectors all having the same norm. 2. A method as claimed in claim 1, characterized in that, for each row, the vectors respectively formed by all the blocks of said row are orthogonal to each other. 3. The method of claim 1, wherein, for each row, said blocks are contained in a plurality of segments, the vectors respectively formed by all blocks of the same segment are orthogonal to each other. 4. The method of claim 1, 2 or 3, wherein the expansion matrix is a rotation matrix. 5. A telecommunications system comprising at least one transmitter configured with at least two transmit antennas and at least one receiver configured with at least one receive antenna, said transmitter comprising: symbol encoding means for generating symbols to be transmitted on the communication channel established between the transmitting antenna and the receiving antenna; sign extension means performed by multiplying a vector formed by concatenating components of each of a predetermined number of consecutive symbols by a predetermined spreading matrix and producing a linear combination of said components; and sending means for sending said linear combination via said transmit antenna over a number of time slices equal to a predetermined number of consecutive symbols, Wherein, the predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmit antennas and forming corresponding vectors all having the same norm. 6. A telecommunications system as claimed in claim 5, characterized in that for each row the vectors respectively formed by all the blocks of said row are orthogonal to each other. 7. A telecommunications system as claimed in claim 5, characterized in that, in each row, said blocks are contained in a plurality of segments, the vectors respectively formed by all blocks of the same segment being orthogonal to each other. 8. A telecommunication system as claimed in claim 5, 6 or 7, characterized in that said spreading matrix is a rotation matrix. 9. A communication device configured with at least two transmit antennas and comprising: symbol encoding means for generating symbols to be transmitted on the communication channel established between the transmitting antenna and the receiving antenna; sign extension means performed by multiplying a vector formed by concatenating components of each of a predetermined number of consecutive symbols by a predetermined spreading matrix and producing a linear combination of said components; and sending means for sending said linear combination via said transmit antenna over a number of time slices equal to a predetermined number of consecutive symbols, Wherein, the predetermined spreading matrix has its rows formed by successive blocks each having a size corresponding to the number of transmit antennas and forming corresponding vectors all having the same norm. 10. The communication device according to claim 9, characterized in that, for each row, the vectors respectively formed by all the blocks of the row are orthogonal to each other. 11. The communication device according to claim 9, wherein, in each row, the blocks are included in a plurality of segments, and vectors formed by all the blocks in the same segment are orthogonal to each other. 12. The communication device according to claim 9, 10 or 11, wherein the spreading matrix is a rotation matrix.

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